Actually, it's pretty easy to do. Print up your own bumperstickers or other "public service announcements" on label paper. Right before you go through the line, make a detour to the men's (or ladies') restroom. Peel off the backing and attach the front side to the bottom of your laptop or other small bag with just a little bit of that stuff they use to hold new credit cards on the paper when you get them in the mail. When you place your laptop in the bag, the label will stick to the bottom to the bin and you will not have drawn the attention of a SPOTNik. This technique also works well at the "recomposure" tables after you've cleared the checkpoint. More people and screeners are likely to see it stuck to a table than in a bin. Oh yeah -- the bin tagging works just as well at airports without bin advertising.

Good luck and Happy 1st Amendment.